Baleen Treasure Trove

Sometimes great surprises do come in very large packages.  Last week, Christmas came early for the archaeological community when a treasure trove of baleen whale fossils was unearthed in the Chilean desert courtesy of a highway expansion project.  Scientists around the world have been buzzing with questions of how the animals got almost a mile inland and why so many died in the same place, and most importantly, everyone is wondering whether these finds present new evidence in the evolutionary record of marine mammals.

While this mass grave has stirred up more questions than answers, researchers are certain of a few things.  Of the 80 individual animals, 25 of the skeletons are perfectly intact, making it one of the largest and best-preserved sites of its time period.  Paleoclimatologists are convinced that they must have died anywhere between 2 and 7 million years ago when the area was a large lagoon.  But the question remains - why did so many animals simultaneously die?  Some have proposed that perhaps a natural disaster such as a landslide or earthquake sealed off the lagoon, trapping the animals inside.  Perhaps they could have beached themselves after becoming disoriented as whale pods still do today.  Other theories include a sudden change in the lagoon water chemistry or even a large tidal wave that pushed them ashore.

Interestingly, these whales weren't alone when they died.  An extinct aquatic sloth, an extinct dolphin complete with two large walrus tusks, and an ancient seabird with an 18-foot wingspan were all also uncovered at the site.  Can you even start to imagine a bird almost as large as a school bus?  Once you have conjured an image of this strange and distant land, picture this unfamiliar ecosystem stretching as far as the eye can see.  Sounds like the beginnings of a C.S. Lewis novel to me!

These discoveries give researchers a window into the past, when the landscape looked dramatically different than it does today.  It also reminds us to keep a healthy amount of skepticism in our lives.  How do we know what we know?  We cannot excavate everything.   And, even when scientists do stumble across the evidence, the best we can do is make educated guesses and let our imaginations fill in the rest.  In this case, the developers wanted all of the skeletal remains moved away from the expansion project but Chilean government officials have protected it in an attempt to prioritize the potential contributions to science.  Thanks to Chile, we'll know a little bit more about ancient life in the Atacama Desert.